1. Field of the Invention
The present invention relates to a noncontrolling type valve for use in a gaslighter, a portable cooking stove and other burners. Such a valve permits a given constant amount of gas to flow to the nozzle when the valve opens.
2. Related Art
A conventional noncontrolling type valve is built in a recess formed in the top plate of a gas container. The recess has a through aperture in its bottom to communicate with the inside of the gas container. A valve body is push-fitted in the recess, and porous filter is positioned between the valve body and the through aperture of the recess bottom, not contacting the valve body and the recess bottom, permitting a given constant amount of gas to flow from the through aperture of the recess bottom to the valve when it is opened.
The porous filter is separate from the recess bottom and from the valve bottom. When the valve is opened, the porous filter will be subjected to gas pressure, and accordingly it will be yieldingly bent upwards. Thus, it is liable to be loosened or deformed with the result that the gas-passing area of the filter varies and that the gas flow rate varies accordingly. When the gas pressure in the gas container increases with the increase of surrounding temperature, the length of the nozzle flame will increase and the flame will become unstable.
The liquefied petroleum gas is liable to stay in the through aperture of the recess bottom because the through aperture is closed by a liquid bubble, which is caused by surface tension. Then, an extra amount of heat (evaporation heat) is required to evaporate the gas trapped in the through aperture of the recess bottom. An insufficient amount of heat will cause incomplete evaporation, which is the cause for unstable flame on the nozzle.